[PATCH 6.18.y] accel/amdxdna: reject command submission on devices without a submit op

[Sasha Levin <sashal@kernel.org>]

From: Doruk Tan Ozturk <doruk@0sec.ai>

[ Upstream commit 38953513d7313992676d4136cd425cdb70c6278e ]

amdxdna_cmd_submit() calls xdna->dev_info->ops->cmd_submit()
unconditionally, but only aie2_dev_ops defines that callback.
aie4_vf_ops (the AIE4 SR-IOV virtual function) does not, so a user
AMDXDNA_EXEC_CMD ioctl on an AIE4 device reaches a NULL function-pointer
call and oopses the kernel. AIE4 submits work through a mapped user queue
and doorbell, not this ioctl path.

Reject the submission early with -EOPNOTSUPP when the device provides no
cmd_submit op, so the shared EXEC ioctl is a clean no-op on such devices.

Fixes: aac243092b70 ("accel/amdxdna: Add command execution")
Cc: stable@vger.kernel.org
Found by 0sec automated security-research tooling (https://0sec.ai).
Assisted-by: 0sec:claude-opus-4-8
Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai>
Reviewed-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20260713173030.87541-3-doruk@0sec.ai
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/accel/amdxdna/amdxdna_ctx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/accel/amdxdna/amdxdna_ctx.c b/drivers/accel/amdxdna/amdxdna_ctx.c
index cfee89681ff3cf..3f7e53b1b6ee4a 100644
--- a/drivers/accel/amdxdna/amdxdna_ctx.c
+++ b/drivers/accel/amdxdna/amdxdna_ctx.c
@@ -405,6 +405,10 @@ int amdxdna_cmd_submit(struct amdxdna_client *client,
 	int ret, idx;
 
 	XDNA_DBG(xdna, "Command BO hdl %d, Arg BO count %d", cmd_bo_hdl, arg_bo_cnt);
+
+	if (!xdna->dev_info->ops->cmd_submit)
+		return -EOPNOTSUPP;
+
 	job = kzalloc(struct_size(job, bos, arg_bo_cnt), GFP_KERNEL);
 	if (!job)
 		return -ENOMEM;
-- 
2.53.0